A variant of flexor carpi ulnaris causing ulnar nerve compression.

Anatomical variations of the muscles and nerves around the wrist are common. Knowledge of such variations is derived from 2 sources: anatomical dissections and clinically reported cases. We present a case of duplication of the tendon of flexor carpi ulnaris with splitting of the ulnar nerve. The ulnar slip of the tendon was inserted into the pisiform bone and the radial slip into the proximal phalanx of the ring finger. The anatomical literature and the clinically reported cases of variations of the flexor carpi ulnaris are reviewed.